In an apparatus for successively making plastic bags, as described in Patent Document 1, webs of first and second panel materials are superposed on each other and fed longitudinally thereof. The plastic bags are made by the first and second panel materials, as also in the cases of apparatuses of Patent Documents 2 to 5.
In the case of the apparatus of Patent Document 1, the plastic bags include front, back and one end surfaces. A web of bottom gusset material is supplied to the web of the first or second panel material before the webs of the first and second panel materials are superposed on each other. Then, the front and back surfaces are formed by the webs of the first and second panel materials, while the one end surface is formed by the web of the bottom gusset material.
In this case, the apparatus should comprise a bottom gusset material supply device by which the web of the bottom gusset material is supplied from another supply roll in order to form the one end surface. The apparatus must therefore be complicated in structure and high in cost. When being printed with a pattern, a discrepancy in pattern between the panel and bottom gusset materials is also caused.
On the other hand, in the apparatus of Patent Document 2, a plastic film is slit along its longitudinal slit line so as to be divided into the webs of the first panel and bottom gusset materials before the webs of panel material are superposed on each other. The apparatus comprises a bottom gusset material guide device by which the web of the bottom gusset material is guided and supplied to the web of the first or second panel material. The front and back surfaces are formed by the webs of the first and second panel materials, while the one end surface is formed by the web of the bottom gusset material.
In the apparatus of Patent Document 3, the web of the bottom gusset material is supplied to the web of the first or second panel material and extended along its longitudinal centerline. Then, the web of the bottom gusset material is slit along its longitudinal centerline. The webs of the first and second panel materials are also slit along the longitudinal centerlines thereof before or after the web of the bottom gusset material is supplied. Thereby, the plastic bags are made two by two, each of which includes the front, back and one end surfaces. The front and back surfaces are formed by the webs of the first and second panel materials, while the one end surface is formed by the web of the bottom gusset material. The plastic bags are made two by two using the apparatus that can slit the plastic film along its longitudinal slit line so as to divide into the webs of the first panel and bottom gusset materials, as in the case of the apparatus of Patent Document 2.
In the case of the apparatuses of Patent Documents 2 and 3, the web of the bottom gusset material has therefore not been supplied from another supply roll because the plastic film can be supplied from its supply roll so as to be divided into the webs of the first panel and bottom gusset materials. As a result, the apparatus can be simple in structure and low in cost. When being printed with a pattern, a discrepancy in pattern between the panel and bottom gusset materials cannot be also caused.
By the way, another apparatus has also been proposed to successively make plastic bags using the bottom gusset material. In the case of the apparatus of Patent Document 4, for example, the plastic bags include the other end surfaces in addition to the front, back and one end surfaces. Two webs of the bottom gusset material are supplied to the web of the first or second panel material and extended along the opposite side portions thereof. The front and back surfaces are formed by the webs of the first and second panel materials. Among the two webs of the bottom gusset material, the one end surface is formed by one web of the bottom gusset material, while the other end surface is formed by the other web of the bottom gusset material. The plastic bags are made one by one using the apparatus.
In the case of the apparatus of Patent Document 4, a total of three webs of the bottom gusset material can be supplied. Among the three webs of the bottom gusset material, one particular web of the bottom gusset material has a width two times as much as a width of the two other webs of the bottom gusset material. The particular web of the bottom gusset material is supplied to the web of the first or second panel material and extended along its longitudinal centerline, while the other webs of the bottom gusset material are supplied to the web of the first or second panel material and extended along the opposite side portions thereof. The particular web of the bottom gusset material is slit along its longitudinal centerline after being supplied, as in the case of the bottom gusset material of Patent Document 3. The webs of the first and second panel materials are slit along the longitudinal centerline thereof before or after the webs of the bottom gusset material are supplied. The plastic bags are made two by two, each of which includes the front and back surfaces formed by the webs of the first and second panel material. The one end surface is formed by the particular web of the bottom gusset material, while the other end surface is formed by the other webs of the bottom gusset material. The apparatus can make the plastic bags two by two.
However, especially in the case of the apparatus by which the plastic bags are made two by two, a total of three webs of the bottom gusset material should be supplied to the web of the first or second panel material. Thus, in the case of the apparatus of Patent Document 2, even though the plastic film is divided into the webs of the first panel and bottom gusset materials, other webs of the bottom gusset material should be supplied from other supply rolls. The apparatus must therefore be complicated in structure and high in cost. When being printed with a pattern, a discrepancy in pattern between the panel and bottom gusset materials is also caused.
There is another apparatus by which the plastic bags are made two by two. In the apparatus, two webs of the bottom gusset material are supplied to the web of the first or second panel material and extended along the opposite side portions thereof. Then, the webs of the first and second panel materials are slit along the longitudinal centerline thereof. The plastic bags are therefore made two by two, each of which includes the front and back surfaces formed by the webs of the first and second panel material and the one end surface formed by the webs of the bottom gusset material.
However, the webs of the bottom gusset material should be supplied from other supply rolls. A discrepancy in pattern is also caused.
In the case of the apparatus of Patent Document 4, two webs of the bottom gusset material must be supplied to the web of the first or second panel material when making the plastic bags one by one. The webs of the bottom gusset material must therefore be supplied from other supply rolls, as also in the case of the apparatus described above. A discrepancy in pattern is also caused.
In the case of the apparatus of Patent Document 5, the web of the first or second panel material is guided by a panel material guiding device during the feed of the webs of the panel materials. The web of the first or second panel material is folded along its one side edge and folded back so as to form a folded portion. Therefore, the front and back surfaces are formed by the webs of the first and second panel materials, while the one end surface is formed by the folded portion.
Another apparatus by which the plastic bags are made two by two is also described in Patent Document 5. In the apparatus, the web of the first or second panel material is folded along its opposite side edges and folded back so as to form the folded portions. Then, the webs of the first and second panel materials are slit along the longitudinal centerline thereof. The plastic bags are therefore made two by two.
Therefore, in the apparatus, the web of the bottom gusset material is supplied to the web of the first or second panel material and extended along the longitudinal centerline thereof. Then, the web of the bottom gusset material is slit along its longitudinal centerline. The webs of the first and second panel material are also slit along the longitudinal centerline thereof before or after the web of the bottom gusset material is supplied. The plastic bags are made two by two, each of which includes the one end surface formed by the web of the bottom gusset material and the other end surface formed by the folded portions.
However, another bottom gusset material must be supplied from another supply roll. A discrepancy in pattern is also caused.
It is therefore an object of the invention to provide an apparatus for successively making the plastic bags, wherein the bottom gusset material should not be supplied from another supply roll and a discrepancy in pattern should not also be caused.
Patent Document 1: JP 4,436,521B
Patent Document 2: JP 4,469,412B
Patent Document 3: JP 4,429,379B
Patent Document 4: JP 4,526,592B
Patent Document 5: JP 3,655,627B